Method and apparatus for refinincj reclaimed rubber



Jan. 29, 1929.

J. F. FISHER ET AL METHOD AND APPARATUS FOR REFININQ RECLAIIED RUBBERFiled F013. 28, 1928 3 Sheets-$heet 1 A Mg ax Jan. 29, 1929. 1,700,287

J. F. FISHER El AL METHOD AND APPARATUS FOR REFINING RECLAIIED RUBBERFt] l= 928 SSheets-Sheet 2 1416M 466406 flia/llz @ifim, MR7

C mjm'zfm Jan. 29, 1929. 1,700,287

J. F. FISHER El AL METHOD AND APPARATUS FOR REFINiNG RECIJAIMEL RUBBERFiled Feb. 28, 1928 3 Sheets-Sheet 5 Patented Jan. 29, 1929.

UNITED STATES L'iiidg? PATENT OFFICE.

JOHN F. FISHER AND VJAL'LACE R. GILLAM, OF PHOENIXVILLE, PENNSYLVANIA,AS-

SIGNORS TO THE PHILADELPHIA RUBBER W'OEKS COMPANY, OF WILMINGTON,DELAWARE, A CORPORATION OF DELAWARE.

METHOD AND APPARATUS FOR Application filed February This inventionrelates to procedure and apparatus for refining reclaimed rubber bypassing it between closely set mill rolls, to crush and plasticize thesmall lumps or granulcs in the stock and reduce it all to substantiallythe same texture or consistency. The stock is sheeted in its passagebetween the rolls and the side margins of the sheet contain coarserparticles or granules than the rest of the sheet, which probablyv isbecause of the fact that the rolls are slightly crowned with a view tomaintaining a close setting of the rolls throughout their lengthnotwithstanding the slight springing of the rolls under the very highpressure of the stock passing in a thin film or sheet between them, thecrowning of the rolls perhaps being somewhat excessive and the particlesin the bank of stock apparently migrating toward the ends of the rollsas an incident of being' repeatedly or continuously rejected at the nipof the rolls.

The granular margins of the sheet require to be passed again through themill to reduce them to the proper state and to this end the commonpractice has been to scrape them from the roll upon which the sheet iscarried at a different position from that at which the main, middleportion of the sheet is scraped from the roll, so that they may readilybe separated from the properly refined stock, and because of theirhighly granular character they have produced variations in the grade ofthe stock in which they have been given their second passage through themill, especially since, so far as we are aware, no effort has been made,prior to our invention, to effect a uniform, proportional distributionof them in the new stock with which they are mixed in their secondpassage through the mill.

Another cause of non-uniformity in the finished stock has been theescape of highly granular stock past the dams at the ends of the milland the unintended mixing of such stock with the finished product as thetrimmed marginal strips, with lumps of the granular stock insecurelyhanging to them, are lifted back into the mill.

Our chief objects are to provide uniformity in the refined product; toprovide procedure and apparatus whereby the better product may be hadwith less labor than heretofore has been required for producing REFININGRnoLArMED RUBBER.

28, 1928. Serial No. 257,678.

the less uniform and less desirable product; and to increase theproduction of the mill. the accompanying drawings:

Fig. l is a transverse section of a mill embodying and adapted to carryout our invention in its preferred form.

Fig. 2 is a front elevation of the same.

Fig. 3 is a fragmentary plan view of the. mill.

Fig. 4 is a perspective view of a scraping knife and its mountingconstituting a part of the apparatus.

Fig. 5 is a perspective View of a part of the bin adapted to receive therefined stock.

Referring to the drawings, the mill comprises the usual pair of rolls10, 11 mounted in end standards 12, 13 and provided with the usualdriving means. The knife assembly l-i for scraping the middle zone 15 ofsheeted stock from the roll 10 and the bin 16 for receiving the finishedstock scraped from the roll by the knife str eture 14: also are ingeneral of the usual construction.

\Ve have discovered that escape of stock from the stock bank 17 in themill through the small clearance space between splice plate 18 and therolls may be substantially prevented and the granular condition of theside margins of the sheet also may be materially reduced by radicallyincreasing the width of the splice as compared with the prior art,although the clearance between the splice plate and the rolls bepermitted to remain the same.

Having thus provided means for producing sheeted stock having sidemargins comparatively free from coarse granules and clinging granularparticles we provide means whereby the marginal strips conveniently maybe removed from the roll 10 separately from the sheet 15 of finishedstock and fed back into the mill in suitable proportion to thesuccessive charges of new stock and so as to be well intermixed with thelatter in again passing through the nip of the rolls.

For this purpose, and also to prevent dirt and particles of new stockfrom being dropped onto the accumulation of finished stock in the bin 16as the successive charges of stock are placed in the mill, we providean. inclined shield and table 21 over the bin 16 with its lower marginextending close to the roll 10 just over the knife structure 14, themember 21 being adapted to receive accumulations of side margin stock 22scraped from the roll 10 by scraping knives 23, 23 mounted. uponrespective brackets 24, 2e! near the respective ends of the roll overthe table member 5 31. Each knife bracket 24.- is preferably formed.with a projecting plate 25 extending away from the roll 10 in suchposition at the inner end. of the knife that any part of the accumulatedmarginal stock re-adhering to the roll 10 and. starting to be liftedthereby toward the bank 17 of stock in the mill. will be snubbed aboutthe plate 25 and thus caused to break its adhesion to the roll and dropback into the accumulation of stock, the plate thus causing the stock asit accumulates to be rolled into a roughly ball-shaped mass.

As the marginal. stock may be allowed to accumulate locally at the endsof the roll the knife may be formed with a straight scraping edge, whichis preferable to employing an obliquely disposed knife requiring ascraping edge curved in three dimensions to it the roll.

\Ve preferably provide means such as the removably mounted. clips 26upon the bin 16, at the upper corners thereof adjacent the roll 10 andextending nearly to the roll and to the knife, to prevent crumbs ofstock, espccially such as are carried by the roll or form at the end ofthe knife, from dropping into the refined stock in the bin. The clipsare removably mounted to permit easy removal of the knife.

In the operation of the apparatus, charges of new stock of equal sizeare brought from a suitable source at substantially equal intervals oftime, as determined by the size of the bank 17 in the mill, and as eachnew charge of stock is brought to the mill it is laid upon the inclinedtable 21, where the accumulations of marginal stock 22 adhere to it, andthe combined. mass is pressed against the roll 10, which carries it overto the bank 17, the plates 25 serving to effect a cutting or breaking ofthe accumulation of marginal stock from that still spread upon the roll,so that a new accumulation will. form and be rolled into a ball.

As the struis of marginal stock 522 accumulate upon the table 2 tsubstantially uniform rate each of the periodically presented charges ofnew stock, each of standard size, iarries with it into the bank 17 asuitably proportioned. amount of the marginal stock, and as eachinstallment of the marginal stock goes into the bank with acomparatively large amount of the new stock it undergoes an intermixingtherewith in the bank while the bank is large and becomes thoroughlydistributed therein before passingr again through the nip of the rolls.

Thus the several advantages set out in the above statement of objectsare obtained, the proper feeding back of the marginal stock beingreduced to a: mere matter of feeding the mill with equal charges of newstock at intervals determined by the size of the bank and theproportioning of th marginal and the new stock being automatic. Thelabor of separately handling the nun-meal stock and of gathering updroppings eliminated, as is also the contamination of the finishedproduct.

As nuuliiications are possible within the scope of our invention we donot wholly limit our claims to the specific apparatus or to the exactprocedure herein described.

l ve claim:

1. The method of refining reclaimed rubber which comprises passing therubber through a mill to form it into a continuous sheet, continuouslydividing the sheet lengthwise into strips and causing the strips toaccumulate in different piles to separate different grades of stockcontained in the sheet, and from time to time feeding successiveaccumulations of one of the grades of sheeted stock back into the millwith proportional amounts of new stock.

2. A method as defined in claim 1 in which successive charges of newstock of substantially the same size are passed into the mill atapproximately equal intervals of time and are combined with thecorresponding accumulations of the sheeted stock fed back to the mill.

3. The method of refining reclaimed rubher which comprises passing therubber through a mill to form it into a continuous sheet, continuouslydividing the sheet lengthwise into strips to separate stocks ofdiiferent grades contained in the sheet, and feeding the stock of onegrade back into the mill substantially in constant ratio to the feedingof new stock into the mill.

4. A refining mill comprising a pair of rolls, a plurality of knivesadapted to scrape respective zones of the sheeted stock from one of therolls, means for supporting apart from each other the accumulations ofstock from the respective knives, one of the supporting means beingadapted to support the accumulation of stock therefrom in positionconveniently to be combined with a charge of new stock being passed tothe mill, and cnd-dam members for the mill rolls each of such width in.proportion to its clearance with relation to the rolls as substantiallyto prevent the escape of stock through the clearance space.

5. A refining mill comprising a pair of rolls, a plurality of knivesadapted to scrape respective zones of the sheeted stock from one of therolls and means for supporting apart from each other the accumulationsof stock from the respective knives, one of the supporting means beingadapted to support the accumulation of stock therefrom in positionconveniently to be combined with a charge of new stock being passed tothe mill.

6. A refining mill comprising a pair of sheeting rolls, a scraper forremoving the middle zone of the sheet of stock for one of the rolls, atable member mounted over said scraper, and a'pair of scrapers forremoving the marginal zones of the sheet from the roll at such positionsthat the stock of the said zones will accumulate upon the said tablemember.

7. A mill as defined in claim 6 in which each of the last mentionedscrapers is formed with a straight scraping edge.

8. A refining mill comprising a pair of rolls, a knife adapted to scrapea strip of sheeted stock from one of said rolls, means for supporting anaccumulation of stock from said scraper, and a member so formed andpositioned that stock of the said accumulation adhering to the roll willbe snubbed about the said member and thus caused to break its adhesionto the roll.

In Witness whereof We have hereunto set our hands this 20th day ofFebruary, 1928.

JOHN F. FISHER. WALLACE R. GILLAM.

